Crunches, he says, supersede sit-ups if you’re looking to improve your abdominal strength, “because they allow you to work this area without using your hip flexors.”

“When you do a sit-up, you use your psoas muscles to sit up the entire way. This means that your abdominals, which are essentially the muscle you’re trying to work, are not receiving the full amount of benefits that they would if you did a round of crunches.”

“If you’re crunching correctly, you will only exercise the abdominal muscles, and your core will stay engaged the entire time, meaning your muscles have more time under tension, and thus have more opportunity to improve,” says Lucas.

Of course, this does not mean the sit-up is obsolete. This exercise is imperative for core strengthening, as it works the chest, neck, lower-leg muscles, hips and lower back.

Ben’s tips to complete a correct crunch:

To do a correct crunch, lie flat on your back with your knees bent and your feet about 10-15 inches from your butt. You can have your hands either crossed on your chest, by your side, or up near your ears.

Suck your stomach in and without moving your lower body, curl your upper torso up and in toward your knees, until your shoulder blades are as high off the ground as you can get them. Only your shoulder blades should lift, keep your back on the ground.

Once you get as high up as you can, hold for a second or so then slowly lower back to starting position.